Answer:
(a) 
(b) 
(c) K.E. = 21.168 J
(d) 
Explanation:
Given:
- mass of a block, M = 3.6 kg
- initial velocity of the block,
- constant downward acceleration,
That a constant upward acceleration of 
is applied in the presence of gravity.
∴
- height through which the block falls, d = 4.2 m
(a)
Force by the cord on the block,
∴Work by the cord on the block,
We take -ve sign because the direction of force and the displacement are opposite to each other.
(b)
Force on the block due to gravity:
∵the gravity is naturally a constant and we cannot change it
∴Work by the gravity on the block,
(c)
Kinetic energy of the block will be equal to the net work done i.e. sum of the two works.
mathematically:
K.E. = 21.168 J
(d)
From the equation of motion:
putting the respective values:
is the speed when the block has fallen 4.2 meters.
I think it is c density and temperature
The force applied to an object is said to be a product of its mass and the acceleration. For this case, acceleration is the reading on the gravitometer. We calculate as follows:
F = mg
39.36 N = m(9.83 m/s^2)
m = 4.00 kg
Hope this answers the question. Have a nice day.
The average kinetic energy of a gas particle is directly proportional to thetemperature. An increase intemperature increases the speed in which the gas molecules move. Allgases at a given temperature have the same average kinetic energy. Lightergas molecules move faster than heavier molecules.
